I've done everything I could possibly think of to try to solve the problem. Had the radiator checked and flushed, I was told its still solid, my clutch fan works great, new water pump, and new T-stat but the car still overheats on the highway. When I'm going about 75 the temp gauge is on the first warning line just to the right of the symbol.... Is this normal?

 

Something is blocking your airflow in the front, OR your waterflow through the radiator.

Based on the things you've already changed, I would think that you may need to flush the engine block and see if that helps. Changing out the radiator doesn't help much if the crap in the block flows back to the radiator and clogs it up again. When I had my radiator rebuilt (re-rod and boil out), they said it would need to be flushed to keep the block cleaned out, otherwise it would clog up again in short order.

Hook a hose up to the heater inlet at the back of the block and remove your lower radiator hose - this will allow the block to flush. There is also a 12mm bolt on the driver's side center housing just below the plugs that is the main block drain for coolant.

Give that a shot and report back,

 

And to answer your question, not it's not normal, and try not to drive the car at that speed until the overheating issue is resolved - engine might get damaged.

What kind of t-stat do you have in the car?

P.S. fan clutch wouldn't affect much temp at 75 mph.

 

maytbe he has wrong thermostat

 

I had a similiar problem (my car is currently being transformed ). When driving on the highway at 3 grand in 5th and the lights on it sits just below half way. Found out its my number plate disrupting airflow to my radiator. I have my number plate in the middle of the front rio/bumper and it probably hangs down about 4-5cm. Not much but enough. When I took it off, noticed a big difference.

 

I'm having the same problem. I don't have the under tray installed. In Las Vegas temps during the day is in the 100's. Took car out at midnight when temp was in the high 80's and ran alot cooler 185 deg. Looking for a under tray now. Also can a make some kind of scoop to get the airflow to my radiator? My front spoiler is restricting the air. Thanks. Look at my web site for a pic of my spoiler

 

well i flushed out the radiator and the engine block like u said a few times. I filled the system with water and ran the car for about 7 minutes in between to re-circulate the old fluid and clean out any extra crap. My front air dam and everything else is stock but I do have a license plate that hangs down... I'll try moving it then taking out on the highway tomorrow to see if it helps. Thanks a lot!

 

Any chance this could actually be an oil cooling issue? From what I understand, a large percentage of the engine cooling is accomplished through the oil cooler. What do all you experts think?

 

I used to have the exact same problems, I bought a lower temp t-stat, and it made city driving temps lower, but highways were still pretty high. I don't wanna scare you but that engine just broke 3 weeks ago, and the new engine with the exact same cooling system, including same water pump, the temps are much lower. highway temps are like 1/5th up the gauge, and doesn't budge. how many miles on your engine. check your OMP. As i understand it, if the engine doesn't get enough luberication the friction is able to produce more heat

 

Check radiator CAP. My engine once overheated due to a faulty cap.

 

When I put the skid plate back on it helped a little. I think the idea is it keeps air moving through the radiator instead of under it.

 

alright so i took it out today and ran about 20 miles strait going anywhere from 65-75 and it ran cooler, the temp guage read just to the left of the 1st warning line instead of to the right of it, but this is still hotter than it should be running at. As for a faulty rad cap can i dont think my cap is stock can i take the cap off my gsl-se and use it on my car (a gsl)or will this not work?

 

if your coolant reservoir is always full with signs of over filling, then change the radiator cap. With the engine running hot at 75MPH, remove the t-stat completely. If it continues to run hot, then your problem is the radiator. Get it ROD-OUT as FLUSHING will NOT remove any blockage.

No t-stat is good but, on a stop and go traffic, the coolant flows tooo fast. Instead, I prefer to use a gutted t-stat (no spring) to slow down the flow and allow the coolant to absorb more heat from the engine.

Good luck

 

Also depending on $ available, you might wanna consider just replacing the radiator for a new one. I did that last year when having serious overheating issues and voila! all problems gone.